Center and Isochronous Center Problems for Quasi Analytic Systems  

作　　者：Yi Rong Liu Ji Bin Li 

机构地区：[1] Department of Mathematics, Zhejiang Normal University, Jinhua, 321004, P. R. China [2] School of Science, Kunming University of Science and Technology, Kunming, 650093, P. R. China

出　　处：《Acta Mathematica Sinica,English Series》2008年第9期1569-1582,共14页数学学报（英文版）

基　　金：the National Natural Science Foundation of China (10671179 and 10771196);the Natural Science Foundation of Yunnan Province (2005A0092M)

摘　　要：This paper considers the problems of determining center or focus and isochronous centers for the planar quasi-analytic systems. Two recursive formulas to determine the focal values and period constants are given. The convergence of first integral near the center is proved. Using the general results to quasi-quadratic systems, the problem of the isochronous center of the origin is completely solved.This paper considers the problems of determining center or focus and isochronous centers for the planar quasi-analytic systems. Two recursive formulas to determine the focal values and period constants are given. The convergence of first integral near the center is proved. Using the general results to quasi-quadratic systems, the problem of the isochronous center of the origin is completely solved.

关 键 词：generalized focal value center integral periodic constant isochronous center quasi-analytic planar differential system 

分 类 号：O175[理学—数学]